Belt-operated motor cut-out



D. G. DAWKIQNS ET AL 1,713,171

BELT OPERATED MOTOR CUT-OUT 2 Shets-Sheet 1 Filed Jan. l8, 192

I /8 /6 7 I q f iuwavzfiiil y7f7 jifiwil F GLENNH BOWL U5 lNVENTORS uiwi/Qugww ATTORNEY May 14, 1929.

Filed Jan. 18, 1928 2 Sheets-Sheet 2 11OVOLTS P 4 M a m D a ME 4 H NH mm 0 5L 6 a ll\ 6m 7 2 2 F a .f 2 W Z nlT b l i R w [1% a m 01 1 '7 M w W 0LT \l/ii w 2 m O 033 T c s w c a I. R D o m. L T N m 0 o L. M c

CIRCUIT OPEN BELT MBELT GLENN H'BOWLUS DON G DAWKINS INVENTOR5 A TTORNEYS.

Patented May 14, 1929.

UNITED STATES PATENT OFFICE.

DON G. DAVVKINS AND GLENN H. BQW'LUS, F LOS ANGELES, CALIFORNIA.

BEL'I OPELPJATED Ii'IOT'iI IR. CUT-OUT.

Application filed January 18, 19558.

Our invention relates to safety devices and in particular to a device that will prevent operation of a belt on which the alignment is faulty and which, therefore, tends to run with part of the belt over anging the edge of the pulley. Such condition of operation not only reduces the e'llective width of the belt but also produces unequal strain in adjacent parts of the belt and also may cause fraying of the edge due to rubbing against the bearing pedestal or other adjacent parts.

Our invention is particularly applicable to installations of a temporary nature in which, due to lightness of foundations, alignment of the belt is apt to be changed by the shifting of the foundation. It will then be necessary for mechanics to realign the belt by adjustment of the positions of the pulleys and until this is done the device will frustrate any attempt to operate the belt in its condition of misalignment.

In our belt operated motor cutout we arrange two triggers so that the belt as it starts off the pulleys strikes either one of them. The motion imparted to the trigger we utilize to open or close the electric circuit energizing or (lo-energizing the lowvoltage release thru which the motor is operated.

We attain these objects by the mechanism illustrated in the accompanying drawing in which Fig. 1 is an elevation of a preferred embodiment of our present invention, showing it mounted over the belt.

Fig. 2 is an elevation of Fig. 1, partly in section.

Fig. 3 shows a preferred location of our present invention with relation to the belt pulleys.

Fig. 4: shows a preferred manner in which our motor cutout may be electrically connected,

Fig. 5 illustrates an adaptation of our invent-ion to the protection of vertical belts, and

Fig. 6 is an isometric view of the device illustrated in the preceding figure.

Referring to the drawing, Figs. 1, 2 and 3, a belt is indicated at 1 running on a pulley 2. The triggers 3 consist of small steel rods of a size suitable to the belt on which they work. These triggers are secured to a common shaft 4 which is adapted to rotate in bearings formed in the legs 5 and 6 of the Serial No. 247,615.

frame 7. The triggers ordinarily hang vertical about an inch away from the edge of the belt this of course depending on the size of the belt. The frame 7 is secured to a suitable support 8 to hold it rigidly in place over the belt. On 6 a vapor proof box 10 is provided. Shaft 4- passes thru leg 6 into this vapor proof boX and carries a disc 11 made of balrelite, fiber or other suitable insulating material. A stuffing box 12 surrounds shaft 4 where it enters the box 10. Within box 10 two brushes 13 and 14 are arranged to contact with the flat radial faces of the disc 11, the points of contact of the brushes being directly opposite each other through the disc. A pin 15 passes through the disc and is so located that a circuit is completed through the brushes and pin when the trigg rs hang in their normal vertical position. The brushes are secured in a nonconductii material in the vapor proof box with the crminal posts extending through the box. iVire leads 16 one from each brush lead. to the low-voltage release coil. The low-voltage release must be connected in series with the brushes in our belt operated motor cutout.

A preferred manner of electrically connecting our device is shown in Fig. 4, in which 17-17l7 are the usual power line connections, 18 is a manually operated starter, such as is commonly used on squirrel cage induction motors, equipped with a lowvoltage release attachment 19. From the starter 18 the connections 20 and 21 are made to the cutout 10 (detailed in Fig. 1) and to the holding coil of the low-voltage release 19 as shown. Connections 20, 21 and 22 are made to the motor. A separate 110 volt circuit z324.- is connected to the signal lamp 25 through a switch 26 and circuit breaker 27, which are connected to an extension of the motor starter armature 28. In the hookup here illustrated these eonnections are made in such manner that when the switch is closed and the armature held up by the coil, the motor then being in operation, the lamp circuit is open and the signal lamp extinguished, while the cutting out of the motor by the release of the armature will simultaneously close the lamp circuit and light the lamp. If in place of holding coil, such as illustrated, a trip coil is used, the connections to the lamp circuit should be made in such manner that this circuit will be closed and the lamp lighted when the armature is drawn up by the trip coil.

In operation, when the belt starts to run off the pulley, it strikes one of the triggers and causes it to swing (Fig. 2). The motion rotates the disc and moves the pin from between the brushes, consequently opening the circuit holding shut the switch in the low-voltage release, and the motor is thus stopped before the belt has done any damage. The momentum of the moving pulley is usually sufficient to rccenter the belt on the pulleys.

It is to be noted that the belt is not held on the pulley by the physical action of the triggers restraining it: from running oit'. Rather the triggers stop the power input to the belt and, when slipping is due to o. load the tendency to slip ceases when thetorque of the motor is withdrawn. The belt may in such case reccnter itself, or it; may

remain in the position at which it enga ed.

the trigger, or it may even come otl' enti but in any case the belt is no longer being driven by the motor and the danr which such driving of the belt might cause is obviw ated.

Our present invention as illustrated is for use on belts running practically horizon ii By adding a balance weight and a lever justably secured to shaft .1: the normal position of the tr ers can be varie-z, to any de- (71* sired amount. By this simple addition the triggers can be caused. to rest at any :l11 "l-C;, the desired position being nearly per-pew dicular of the belt. This principle can be extended to belts running on pulleys whose axis is vertical.

This modification is illustrated in Figs. 5 and (i in which 1 indicates a short section of the belt running vertically downward, is the cutout proper as detailed in Fig. 3

indicates one of the triggers in its norn'ial position and the dotted litres 3 tile tion into which it is thrown by contact with v the edge of the belt, 29 is an arm rr idly aflixed to one of the triggers and at approxiinately a right angle thereto, and 30 is a broken by the action of whatever type or: relay or low-voltage release may be placed in circuit with the cutout.

Our device, said, may be connected in series with a low-voitage release or other form of holding coil, in which case the cutout will be required to open the circuit of the coil. In place of a holding coil certain devices may be used, known generally as trip coils, which require the energizing oi? the coil in order to disconnect the motor and in this case our device may be used to close the circuitwhen .misal' 'nnent ot the belt occurs, simply by adjustii the rods with reference to the moving c t. This requires :1 revolution ot the 11 on the sh aft 4; to such position that the pin 15 is out of contact with the brushes l3 and 14.- when the triggers are in the position indicated at 3, and in contact with the brushes when the trigger is brought to the position indicated by the invt tron is vapor proof, all ations where tire hazard Y V .1 1:. .ainable vapors Our beltoperati l motor cutout can be placed any place along the belt but it is preferable to locate it over the pulley from which the belt is most iliely to run oil. This can be determined only by the operator.

Vi e claim as our invention:

1. In combination with a belt running on pulleys and driven by an electric motor, said motor tarnished with an electrically operated switch in its supply circuit, a device for automatically stopping said motor comprising: a pair of parallel triggers rigidly secured to a shaft and extending on each side past the edges of said belt, means tor supporting said shaft, and a rotary switch actu ated by said shaft for controlling the circuit through which flows the electric energy which actuates said electrically operated switch.

2. In combination with a belt running on pulleys and driven by an electric motor: a pair of paralle triggers extending on each side of said belt and past its edges; means ifor pivctally supporting said triggers, an electrical circuit breaker operated by a lowroltage release, and means actuated by said triggers for actuating said release and thus stopping the flow oi electricity to said motor should said beltstrike either of said triggers while running.

In witness that we claim the foregoing we have hereunto subscribed our names this 14th day of January, 1928.

DONG; DAlVKlNS. GLENN H. BOlVLUS. 

